This invention relates to orthopaedic footgear, particularly for patients such as diabetics, who have tender feet, or who are prone to having ulcers on the feet.
Footgear with an array of separate sections have been manufactured heretofore by Royce Medical Company, the assignee of the present invention, and prior patents relating to this subject matter include U.S. Pat. Nos. 5,329,705, 5,761,834 and 5,778,565.
These patents disclose insoles which have many hexagonal sections which are independently movable, and which are relatively tall, such as substantially equal to their transverse dimensions or taller, providing a swaying action which reduces shear forces.
As set forth in U.S. Pat. No. 5,761,834:
xe2x80x9cThe grid pattern of resilient sections creates a multiplicity of sections that sway laterally independently of one another in response to forces applied by the foot. Typical soles simply resist lateral foot motion, thereby inducing shear stresses on the bottom of the foot which may cause or aggravate ulcers. Thus, in contrast to typical soles, the grid pattern of independently mobile resilient sections of the present invention constitutes means for reducing shear stresses on the bottom of a foot as the user walks along.xe2x80x9d
However, even with this improved swaying action, it has been determined that in some cases there are peak pressure points which may apply adverse forces to the foot.
It is further noted that the arrangements of the prior art cited above, such as the construction disclosed in U.S. Pat. No. 5,761,834, included construction for precluding xe2x80x9ccompression setxe2x80x9d see Col. 3, lines 5-8 and Col. 8, lines 31-41 of this patent.
In accordance with an aspect of the invention it has been determined that the low shear force action of the footgear, can be improved, and undesirable high pressure points may be reduced or eliminated, by including in the independently movable sections, permanently moldable material. The molding may be accomplished by the use of heat or by other activation arrangements.
Using a heat moldable layer included in the individual sections, the footgear may be heated to a temperature of about 200xc2x0 F. to 350xc2x0 F., preferably 250xc2x0 F. to 300xc2x0 F., and the patient""s foot or a mold of the patient""s foot is applied to the insole to deform the heat moldable material in each section, so that the insole is custom formed to the patient.
With this arrangement, the insole distributes forces from the foot to larger areas of the insole thereby avoiding high pressure points, with the lateral swaying action of the xe2x80x9ctallxe2x80x9d sections still reducing shear forces applied to the foot as the patient walks or stands on the customized insole-lined footgear. The resultant construction has the tall resilient elements or sections permanently deformed with the elements at different heights, and with the upper surfaces at different angles to conform to the shape of the foot during the molding step.
This is in contrast to the use of heat moldable materials used in ski boots or the like without tall insole sections, wherein the increased contact between the footgear and the shoe may actually increase the shear forces applied to the foot. However, in the case of ski boots or the like, where athletes with good foot blood circulation are involved, the increased shear forces normally present no problem. In addition, in a preferred embodiment the use of a xe2x80x9csandwichxe2x80x9d of the heat moldable material between two layers of resilient material in the tall sections can be helpful in avoiding undue xe2x80x9cpackingxe2x80x9d of the heat moldable material so that resilience is still vigorously present in each of the xe2x80x9ctallxe2x80x9d sections.
In accordance with one specific illustrative embodiment of the invention, a footgear has an outsole, an inner layer of woven brush material having a loop construction, and a special insole with hook type material on the lower surface thereof to secure the insole to the outsole. The insole has a thin laminated base formed of an open cell foam with a layer of brush type hook receptive material on both sides and with upwardly extending moldable resilient elements or sections. The moldable resilient elements or sections are arranged in a grid pattern, and are less than three quarters of an inch in their cross sectional extent. In addition they are of substantial height substantially equal to or greater than xc2xe of their lateral extent, with the height being preferably substantially equal to or greater than the transverse extent of the elements or sections. The upper surface of each of the elements is formed of a soft resilient material and the lower surface of the elements has hook type material thereon to engage the hook receptive fabric on the insole base in a manner similar to Velcro(copyright). With the soft upper surface of each of the extended elements remaining in contact with the foot or sock of the patient in use, and the bottom of each element fixedly secured to the insole base, the elements sway or swing back and forth with respect to the base as the patient walks, or shifts position.
In accordance with another feature, when several of the resilient elements are removed to relieve pressure on an ulcerated area, for example, one or more inserts may be provided to place in the resultant opening. This insert or inserts may have a periphery matching that of the removed elements, but may be only a fraction of the height. This insert or inserts has the desired effect of inhibiting the movement of adjacent elements or sections into the hole left by the removal of several elements. The insert may have the shape of several of the removed elements or sections or may be formed of a series of individual inserts.
Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings.